It is known in the art of security and electrically-controlled locks to use keypads and other input devices to provide secure access to buildings or other objects, e.g. safes, automobiles, and the like. In conjunction with this trend, a need has also developed for transmission of various types of functions or information relating to a door secured in a frame. For example, it can be desirable in a security application to provide power across a frame-door gap to the region around a lock in order to energize an actuator, solenoid, motor, etc, or to recharge a battery used in engaging/disengaging the lock, or power an identification device located on the door. It can also be desirable to determine the status or lock-state of the lock, i.e., whether the locking mechanism is engaged or disengaged or whether a door is open or closed. This status information must in some way be acquired and transmitted across the door-frame gap to a monitoring device such as a computer controller.
Prior art systems transfer power and/or data between a door and a door frame using wires that run through a mechanical hinge point or a set of spring loaded contacts that provide an electrical connection across the frame-door gap when the door is in the closed position. The problem with such a wire-based approach is that only very fine wires can be used since such wires must pass internally through the plates of the door hinges to avoid being severed in normal operation or by an intruder. Spring-loaded contacts present a different set of problems relating to contamination of the contacts and the risk of shocking a person passing through the door who might make contact with the ‘live’ contact set on the frame.
What is needed in the art is a robust and efficient system that provides wire-free power transfer between a frame and a door and also enables information or communication transfer, all the while avoiding the above shortcomings of prior art systems.
What is further needed in the art is a compact system that minimizes the area in the door that is taken up by the device or which can utilize the space already provided for a dead bolt, within a mortise lockset, for the compact system.
What is yet further needed in the art is a system wherein its circuitry optimizes power output of the device.
It is a principal object of the present invention to provide a compact, wire-free communications and power transmission system between a door and a frame.